1. Field of the Invention
The present invention relates generally to the generation of multiple electron beams and the use thereof.
2. Description of the Background Art
Electron beam instruments include tools used in automated inspection and review of manufactured substrates. Electron beam instruments also include electron beam lithography systems, and other instruments that use electron beam technology.
Single electron beam systems require very high beam currents to achieve desired throughput at high resolution, therefore are slow when used for applications such as high-resolution inspection of manufactured substrates. A multi-beam system with N beams may provide for N times improvement in throughput (speed) of an inspection system. Single electron beam systems do not, inherently, suffer from cross talk between adjacent electron-optical columns, whereas a parallel system must address cross talk between adjacent columns.
Previous instruments producing multiple electron beams generally utilize purely electrostatic elements. However, these previous instruments are typically prone to substantial aberrations.